From 34ab8645f2e08e842efdd67f8e415b6d46f184f3 Mon Sep 17 00:00:00 2001
From: Luke Shumaker <lukeshu@sbcglobal.net>
Date: Fri, 18 Sep 2015 17:45:34 -0400
Subject: Massive documentation and copyright clean-up.

---
 systemd/nslcd_systemd.go | 165 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 165 insertions(+)
 create mode 100644 systemd/nslcd_systemd.go

(limited to 'systemd/nslcd_systemd.go')

diff --git a/systemd/nslcd_systemd.go b/systemd/nslcd_systemd.go
new file mode 100644
index 0000000..f5d4881
--- /dev/null
+++ b/systemd/nslcd_systemd.go
@@ -0,0 +1,165 @@
+// Copyright (C) 2015 Luke Shumaker <lukeshu@sbcglobal.net>
+//
+// This library is free software; you can redistribute it and/or
+// modify it under the terms of the GNU Lesser General Public
+// License as published by the Free Software Foundation; either
+// version 2.1 of the License, or (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+// 02110-1301 USA
+
+// Package nslcd_systemd does the legwork for implementing a systemd
+// socket-activated nslcd server.
+//
+// You just need to implement the Backend interface, then pass it to
+// Main, which will return the exit code for the process.  Everything
+// but the backend is taken care of for you!
+//
+// 	package main
+//
+// 	import "nslcd/systemd"
+//
+// 	func main() {
+// 		backend := ...
+// 		os.Exit(int(nslcd_systemd.Main(backend)))
+// 	}
+package nslcd_systemd
+
+import (
+	"fmt"
+	"net"
+	"nslcd/proto/server"
+	"os"
+	"os/signal"
+	sd "sd_daemon"
+	"sd_daemon/logger"
+	"sd_daemon/lsb"
+	"sync"
+	"syscall"
+)
+
+type Backend interface {
+	nslcd_server.Backend
+	Init() error
+	Reload() error
+	Close()
+}
+
+func get_socket() (socket net.Listener, err error) {
+	socket = nil
+	err = nil
+	fds := sd.ListenFds(true)
+	if fds == nil {
+		err = fmt.Errorf("Failed to aquire sockets from systemd")
+		return
+	}
+	if len(fds) != 1 {
+		err = fmt.Errorf("Wrong number of sockets from systemd: expected %d but got %d", 1, len(fds))
+		return
+	}
+	socket, err = net.FileListener(fds[0])
+	fds[0].Close()
+	return
+}
+
+func getpeercred(conn *net.UnixConn) (cred syscall.Ucred, err error) {
+	file, err := conn.File()
+	if err != nil {
+		return
+	}
+	defer file.Close()
+	_cred, err := syscall.GetsockoptUcred(int(file.Fd()), syscall.SOL_SOCKET, syscall.SO_PEERCRED)
+	cred = *_cred
+	return
+}
+
+func handler(conn *net.UnixConn, backend nslcd_server.Backend) {
+	defer conn.Close()
+	cred, err := getpeercred(conn)
+	if err != nil {
+		logger.Debug("Connection from unknown client")
+	} else {
+		logger.Debug("Connection from pid=%v uid=%v gid=%v",
+			cred.Pid, cred.Uid, cred.Gid)
+	}
+	err = nslcd_server.HandleRequest(backend, conn, conn, cred)
+	if err != nil {
+		logger.Notice("Error while handling request: %v", err)
+	}
+}
+
+func Main(backend Backend) uint8 {
+	var err error = nil
+
+	sigs := make(chan os.Signal)
+	signal.Notify(sigs, syscall.SIGTERM, syscall.SIGHUP)
+
+	disable_nss_module()
+
+	err = backend.Init()
+	if err != nil {
+		logger.Err("Could not initialize backend: %v", err)
+		sd.Notify(false, "STOPPING=1")
+		return lsb.EXIT_FAILURE
+	}
+	defer backend.Close()
+
+	socket, err := get_socket()
+	if err != nil {
+		logger.Err("%v", err)
+		sd.Notify(false, "STOPPING=1")
+		return lsb.EXIT_NOTRUNNING
+	}
+	defer socket.Close()
+	sock := make(chan *net.UnixConn)
+	go func() {
+		defer lsb.Recover()
+		for {
+			conn, err := socket.Accept()
+			if err != nil {
+				logger.Notice("%v", err)
+			}
+			if conn != nil {
+				sock <- conn.(*net.UnixConn)
+			}
+		}
+	}()
+
+	var wg sync.WaitGroup
+	defer wg.Wait()
+	defer sd.Notify(false, "STOPPING=1")
+	sd.Notify(false, "READY=1")
+	for {
+		select {
+		case sig := <-sigs:
+			switch sig {
+			case syscall.SIGTERM:
+				logger.Notice("Received SIGTERM, shutting down")
+				return lsb.EXIT_SUCCESS
+			case syscall.SIGHUP:
+				sd.Notify(false, "RELOADING=1")
+				err := backend.Reload()
+				if err != nil {
+					logger.Notice("Could not reload backend: %s", err.Error())
+					return lsb.EXIT_NOTRUNNING
+				}
+				sd.Notify(false, "READY=1")
+			}
+		case conn := <-sock:
+			wg.Add(1)
+			go func() {
+				defer lsb.Recover()
+				defer wg.Done()
+				handler(conn, backend)
+			}()
+		}
+	}
+	panic("not reached")
+}
-- 
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